Piezo-electric-crystal apparatus



Feb. 9

A. CROSSLEY PIEZO ELECTRIC CRYSTAL APPARATUS Filed Nov. 24, 1925 Patented Feb'. '9,

UNITED STATESv 1,572,773 PATENT oFFlcE.

ALFRED CROSSLEY, F WASHINGTON', DISTRICT OF COLUMBIA.

PIEZO-ELECTRIC-CRYSTAL APPARATUS.

Application filed November 24, 1925. Serial No. 71,090.

vented certain' new and useful Improvements in Piezo-Electric-Crystal Apparatus,

of which the following is a specification.

My invention relates ybroadly to piezo velectric crystal apparatus and more particularly to a mounting for piezo electric crystals employed for the constant frequency control of electrical circuits.

One of the objects of my invention is to provide a crystal holder by which piezo electric crystals may be hermetically sealed against moisture or gases which effect the proper oscillating characteristics of the piezo electric crystals.

Another object of my invention is to pro- Y vide a piezo electric crystalmounting for connection in an electricalcircuit whereby piezoelectric crystals of different frequency characteristics may bel readily inserted or removed from the electrical circuit for substituting piezo electric crystals of desired frequency characteristics for the control of electrical circuits at desired frequency.

Still another object ofm'y invention is to provide a holder for piezo electric crystals comprising a housing in which the crystal is positioned and electrically connected to terminals extending exteriorly of the casing protecting the crystal from external foreign matter at the same time that the crystal is free to oscillate in its own natural period without hindrance.

My invention will be more fully understood from the specification hereinafter following by reference to the accompanying drawings, wherein Figure l is a perspective View illustrating the piezo electric crystal holder positioned in the mounting; Fig. 2 is a plan view showl ing the crystal holder positioned in its mounting; Fig. 3 is a partial cross-sectional view-v through the mounting and crystal holder showing the arrangement of the piezo electric crystal therein; and Fig. 4 is a front view of the piezo electric crystal .50 holder.

permit quick change from one crystal to another where it is' desired to control an electrical circuit at different frequencies. The crystal is mounted within an insulated housing where it is secured in position in such manner that substantially no mechanical pressure is placed upon the crystal so that it is free to vibrate in its own natural period. The electrical connections are brought out from the housing to cooperate with contacts mounted on the support upon which the crystal holder is positioned. The

`housing is providedwith a lower plate which serves not only as an electrical connection for one side of the piezo electric crystal within the housing, but also as a guide for positionin the housing upon the main support. Re erring to the drawin s in more deta'l, the crystal holder is provided with a Hat parallel metal plate l on' which is secured by means of screws 1a, an insulated circular housing 2. The housing 2 is `fitted with fiat circular insulated cover 3 removably secured thereto by means of screws 3, Between the cover 3 and the annular walls 2, a resilient gasket 4 is placed which hermetically sealsthe holder and thus excludes moisture or gases, which might effect the proper functioning of the piezo electric crystal 5, from the interior of thel crystal holder. The piezo electric crystal 5 is held in place with its lower surface in contact with the top of plate lby means ofV metal pegs 6 lor by -an insulated washer membery which fits over the sides of the crystal and positively spaces the crystal in definite sition with respect to the interior sides o the housing 2 without restrictinnr movement/of the piezo electric crystal 5. l:pper metallic plate 7 lies in contact with the upper surface Of the piezo electric crystal 5 and forms .the upper contact for the crystal.A This late can be square,- oblong or circular, con orming to the shape of the iezo electric crystal 5. The metallic plateg rests gently upon the top of the piezov electric crystal 5 to avoid any restriction in the inherent mechanical vibration of the crystal. In order to hold the plate 7 in a fixed position 4with respect to the top of the crystal, asmall lpin 8 is riveted to the center of the `plate 7 and this pin is free to move vertically in an aperture 10 formed in a downwardly depending resilient guide member 9. The guide member 9 is secured lto the under surface of, the top of the housing by means of a machine screw 14 and nutv 12 and is so formed that it limits the upward movement of the top plate 7 to such an extent that the crystal will not jump clear of the retaining pegs 6 or spacing washer, if such washer is used. That is to say, the space above the piezo electric crystal defined by the lower surface of the resilient member 9 vis so small that the crystal cannot rise vertically to such an extent that it could pass over the retaining pegs 6. This precaution permits the crystal to remain in one fixed position and is therefore not affected by shocks and'jars in transportation or accidental falls or jarring.

A flexible conductor is positioned between the head of the pin 8 and the guide member 9 for establishingr electrical connection between the metallic head 14 and the resilient spring member 19 which is secured at 20 to the insulating mounting 18.

The two terminals for the piezo electric crystal are the bottom plate 1 and the head 14 of the machine screw in the center of the piezo electric crystal housing. By reason of the construction of the mounting 18, with bottom plate 15 secured thereto by means of screws 15, the crystal holder can be quickly attached or detached from the crystal circuit. The bottom plate 15 is in the vform of a metal guide having side portions 16 and 17 between which the bottom plate 1 of the housing 2 slides. -The bottom plate 15 thereby contacts with the plate 1 and establishes electrical connection with the lower surface of piezo electric crystal 5 from which a connection may be taken through guide portion 16, conducting strip 21 which is soldered thereto, the terminal post 22 and the mounting 18 to the electrical circuit which it is desired to control in laccordance with the constant frequency characteristics of the piezo electric crystal contained in the piezo electric crystal mounting.

A number of crystal holders in which 'crystals of different frequency characteristics are mounted may be provided and these holders slipped' in or removed from the mounting in order to change from one crystal to another to se'cure control at different frequencies. This change can be made Very quickly and I have successfully accomplished a change over nine different wavelengths within a time of vthirty (30) seconds. The piezo electric crystal is protected at all times from moisture o1; gases which affect the proper functioning of the crystal by the hermetic closure illustrated.

It is not always necessary to hermitically seal the casing in which the piezo electric crystal is contained for the housing may be such as to offer a mechanical protection for in shape, but it will be understoodzthat other` shapes may be imparted-to the holder and that no limitations uponl the invention are intended other than those imposed by the scope of the appended claims.

What I claim and desire to secure by Letters Patent of the United States is as follows y 1. A piezo electric crystal holder comprising in combination a base plate, a housing secured to said base plate, means for loeating a piezo electric crystal centrally within said housing and contacting with said base plate, means for hermetically sealing said housing to atmosphere, and means for establishing electrical connection with the other side of said piezo electric crystal -and a point `exterior of .said housing.

2. In a piezo electric crystal ap aratus, the combination of a'mounting,'a at conductive base member arranged to detachably engage said mounting, a housing carried by said base member, a piezo electric crystal mounted in said housing with one side thereof engaging said conductive base member and the other side thereof positioned in resilient electrical connection with. a 'con-V tact member external to said housing, and

means carried by said mounting for resili- \ently engaging said contact member for completing electrical connections with said piezo electric crystal.

3. A piezo electric crystal apparatus comprising in combination a mounting, a piezo electric crystal holder arranged to detachably engage said. mounting, said piezo electric crystal holder having Imeans for hermetically sealing a piezo electric crystal therein andY means whereby said piezo electric crystal holder may be mechanically supported by said mounting, and an electrical connection establishedwith said piezo electric crystal.

4. In a piezo electric crystal. apparatus, the combination of a. mounting, a piezo electric crystal holder detachably secured to said mounting, a piezo electric crystal carried bysaid holder, saidl holder being her-y by said supporting member, a piezo electric crystal disposed within said holder and electrically connected with opposite ends of said holder, and means whereby said piezo electric crystal may be electrically connected in a circuit established through contacts on the crystal and yet permit the free access of said supporting member when said holder is atmospheric pressure tothe crystal.

I have shown the crystal holder circular engaged with said supporting member.

' 6. In a piezo electric crystal apparatus,

the combination of a supporting mounting, a piezo electric crystal holder carried by said mounting and detachably engaged therewith, said piezo electric crystal holder comprising a conductive end plate, a housing rising vertically7 therefrom, and a hermetic closure at the' opposite end of said housing, said conductive plate being arranged to support a piezo electric crystal thereon, and means positioned between one face of said piezo electric crystal and the hermetic closure on said housing for establishing electrical connection with said piezo electric crystal, said means extending through said hermetic closure and providing a terminal on the exterior of said housing for .electrically connecting said piezo electric crystal in an electrical circuit. v

7 A piezo electric crystal apparatus comprising 1n combination, a mounting adapted closure arranged to be readily attached to or removed from said mounting, a piezo electric crystal carriedy Within said closure, said piezo electric crystal having its opposite sides connected to terminals which extend `through opposite. ends of said closure, *whereby said terminals may be electrically engaged with contacts carried by said mounting for establishing a detachable connection between circuits connected with contacts on said mounting and opposite sides of said piezo electric crystal.

9. A piezo electric crystal apparatus comprising in combination a support, a plurality of piezo electric crystal holders each containing piezo electric crystals of differing frequency characteristics, means interior of each of said crystal holders for supporting a piezo electric crystal therein in a manner in which the piezo electric crystal is free to vibrate in its own natural period, connections forming terminals on the ex- 4terior of said piezo electric crystal holders providing electrical connections with the opposite faces of each of said piezo electric crystals, and contacts on said support for establishing connection with the terminals of said piezo electric crystal holders Whereby piezo electric crystals of dii'erent\frequency-characteristics may be readily interchanged on lsaid support and connections established with the terminals thereof.

10. A piezo electric crystal apparatus comprising in combination a supporting member, electrical contacts carried thereby, a piezo electric crystal holder arranged to be detachably secured to said supporting member and establish electrical connection with said contacts, said piezo electric crystal holder having a conductive end plate, means for supporting a piezo electric crystal of a particular frequency characteristic upon said conductive end plate, a conductive member arranged to Contact with the upper surface of said piezo electric crystal, a vertically extending pin centrally positioned on said conductive member, a guide member surrounding said pin member and spaced from said conductive plate for a distance less than the thickness of said crystal for preventing said crystal from escaplng from said supporting means under conditions of abrupt vibration.

11. A piezo electric crystal holder comprising in combination a conductive end plate, a housing secured thereto, a closure for said housing opposite to the end closed by said conductive end plate, said end plate having means for supporting a piezo electric crystal of a particular frequency characteristic in laterally spaced relation within said housing, a metallic plate resting on one face of said piezo electric crystal, a pin centrally positioned on said metallic plate, guide means extending from the end closure and embracing said pin, said guide means being spaced from said metallic late for a distance less than the thickness o said crystal for preventing said crystal from escaping from said supporting means under conditions of abrupt vibration.

1:2. A piezo electric crystal holder comprising in combination a conductive end plate, a housing extending' from said end plate, a hermetic closure for said housing, a terminal member extending through said hermetic closure, a U-shaped strip secured to the inner extremity of said terminal` member, with the sides of said strip arranged in planes substantially perpendicular to the axis of said crystal holder, means carried by the inner side of said conductive end plate for centrally locating a piezo electric crystal within said holder, a conductive plate resting on the upper surface of said piezo electric crystal, a pin centrally positioned on said conductive plate and extending through one side of said U-shaped strip, said U-shaped strip overlying said conductive plate for preventing the piezo electric crystal in said holder from escaping from' said means under conditions of abrupt vibration.

13. A piezo electric crystal holder comprising in combination a hermetically sealed closure and means within said closure for securing a piezo electric crystal therein and establishing electrical connection therewith,

at each end of said casing, a piezo electric crystal mounted within said casing, and con-4 nections between each of said terminals and opposite faces of said piezo electric crystal for enabling said crystal to be connected in an electrical circuit, the walls of said receptacle being spaced from at least two .sides of said piezo electric crystal.

16. A receptacle for a piezo electric crystal, comprising in combination a container, an element capable of mechanical vibration mounted Within said container, and terminals on opposite ends of said container and connected with opposite faces of said element, said element bein spaced from one side of said container ifor permitting the free mechanical vibration thereof.

ALFRED CROSSLEY.

lscnAl-MER 1,572,77.-Alfred Crossley, Washington, D. C. PiEzO-ELECTRic-CRYsTAL APPARA-- TUs. Patent dated February 9, 1926. Disclaimer filed May 5, 1933, by' the assignee, Wired Radio, Inc.

Herebyventers a disclaimer-to vclaims 5, 7l,

are in the following words, dto wit:

9, 13, 14, 15, and 16 of said patent, which 5. A piezoelectric crystal apparatus comprising in combination a supporting member, a piezoelectric crystal holder carried 4by said supporting member, a piezo electric c stal disposed within said holder and lectrically connected with opposite .ends of said holder, and means whereby said piezo lectric' crystal may be electrically connected in a circuitl established through contacts on 4said supporting member when said holder is engaged with said supporting'member.

7. A piezo electric crystal apparatus comprism in combination, a mounting adapted to receive one of a plurality of interchangeab e piezo electric crystal holders,

means for4 guiding said piezo electric crystal holder into said mounting and for establshing electrical connection with the piezo electric crystal carried -by said holder, whereby piezo electric crystals of different frequency characteristics may be readily inserted or removed from an .electrical control circuit.

l9. A piezo electric crystal apparatus vcomprising in 'combination a support, a

, plurality of piezo electric crystal olders each containing piezo electric crystals of differing frequency characteristics, means interior of each of said crystalholders for lsupporting a piezo electric crystal therein in a manner 'in which the piezo electric crystal is free to vibrate in" its own natural period, connections forming terminals On the exterior of saidpiezo electric crystal holders providing electrical connections with thev opposite faces of each of said piezo electric crystals, and contacts on said support for establishing connection with the terminals of said piezo electric crystal A holders whereby piezo electric crystals. oi"y different .frequency characteristics may be readily'interchanged on said support and vconnections established with the terminals thereof.

13. A piezo 'elec-tric crystal holder comprising in combination a hermetically sealed closure and means within said closure for securing a piezo electric crystal therein and vestablishing electrical connection therewith, while permitting the free vibration of said piezo electric crystal with substantially no restriction.

"14. A piezo electric crystal holder comprising in combination a hermetically sealed container, a piezo' electric crystal centrallyy positioned in said container and resilientmeans for establishing electrical connection with said piezo electric crystal within said container for permitting the free mechanical vibration thereof with substantially no restriction.

15. A receptacle for housing a piezo electric crystal, comprising a casing, aterminal at each end of said casing, a piezo electriccrystalmounted within said casing, and connections between each of said terminals and opposite faces o f said piezo electric crystal for enabling said crystal to be connected in anelectrical circuit, the walls of said receptacle being spaced from at least two sides of said piezo electric crystal.

16. A receptacle for a piezoelectric crystal, 'comprising in combination a container an element capable of mechanical vibration mounted within said container, and terminals on opposite ends of said container and connected with opposite faces of said element, said element bein spaced from one side of said container for permitting the free mechancal'vibration t ereofl [O cwl Gazette Mary 80, 19331.] 

